Sukkot is also called the "Feast of Ingathering." It is a harvest festival, a time of great rejoicing and thanksgiving over the bounty that God has provided. This image also carries within itself the ultimate prophetic meaning of the harvest. It is indeed a celebration of ingathering, but not only in a agricultural sense, but in relation to the souls of men.

In Numbers 29, we are told that on each of the first seven days of Sukkot the same sacrifices are offered with the exception of the number of bulls that were to be slain. On the first day there were 13, then 12 the next day, then 11 the next day and so on until the seventh day when there were seven. This makes a total of 70 bulls, the number traditionally understood to represent the nations of the world. God had called Israel to be a priestly nation, therefore, it was only natural that they do as a nation what priests were supposed to do - offer sacrifices on behalf of all nations to bridge the gap between them and God.

This is also connected to the prayers for rain that are part of the concluding Sukkot liturgy. Rain is both a picture of the word of God and the Spirit of God (Deuteronomy 32:2 and Isaiah 55:10, Ezekiel 39:29 and Isaiah 32:15), symbolic of that which is needed to prepare the hearts of the nations in the same way as natural rain was needed to achieve the agricultural harvest.

The sacrifices offered on behalf of the nations were to atone for sin. The outpouring of the Spirit on all humanity (Joel 2:28) would cause the transformation in their hearts and ultimately bring them in to the kingdom of God alongside of Israel.

On the eighth day only one bull was offered and that was specifically for Israel. One traditional comment on this says, "On the seven days of the feast of Tabernacles, the Israelites offered seventy bullocks for the seventy nations of the world. God said: 'Therefore on the eighth day there shall be an assembly for yourselves.'" (Num. 29:35)